Field of the Invention
The present invention relates to human-powered drive trains for vehicles.
Background
Human-powered vehicles, such as bicycles, scooters, wheelchairs, and others, involve a variety of drive train designs, such as standard bicycle pedals on crank arms (for a bicycle), pushing the vehicle with a foot (for a scooter), pushing the wheels manually (for a wheelchair) and so on. The manually pushed designs, such as scooters and wheelchairs, are inefficient. The pedal-powered designs, such as bicycles, suffer from a different problem, namely that the feet have to move in an extremely constrained path (circle), which is un-ergonomic and offers inefficient leverage for a large portion of the pedal stroke.
To address the problems, lever action drives have been developed. Such drive trains convert reciprocating motion into rotary motion, avoiding dead spots and inefficiency, and in some cases allowing two or more driving limbs to function independently. However, the existing designs are relatively complex and expensive. A simpler design is needed for converting reciprocating motion into rotary motion.